A bonding agent system, such as those disclosed in our assigned U.S. Pat. No. 4,090,983, including MT4 (reaction product of 2.0 moles of tris 1(2 methylaziridinyl)phosphine oxide, 0.7 mole adipic acid, and 0.3 mole tartaric acid), HX752 (bis isophthaloyl 1(2 methyl) aziridine), and BIDE (butyliminodiethanol) in combinations of 0.10% to 0.20%, 0.10% to 0.20%, and 0.02% to 0.05% weight percent range respectively of a hydroxy-terminated polybutadiene propellant composition achieves improved propellant aging and low temperature physical properties. Other bonding agents such as BA114, the reaction product of equimolar quantities of 12-hydroxystearic acid and tris[1-(2-methylazirdinyl)] phosphine oxide, have also imparted very desirable mechanical properties to composite propellants.
Other types of compounds including certain amine compounds such as TEPAN, partially cyanoethylated tetraethylene pentamine, have long been used in the propellant industry as bonding agents in composite propellants containing ammonium perchlorate (AP). They greatly improve the mechanical properties of such propellants by chemically bonding AP particles to the binder matrix. TEPAN is also known to facilitate processing relative to other bonding agents since the mix viscosity of the propellant is not increased as much by TEPAN as it is by most other bonding agents. The disadvantage of using amine bonding agents is that ammonia is liberated during the mix and cure cycles due to displacement of ammonia from AP by amine groups in the bonding agent. The amine-ammonium perchlorate reaction requires subsequent ammonia removal from the mix because any residual ammonia will consume part of the isocyanate curing agent and thus interfere with propellant cure. If the amine-AP reaction and removal of ammonia is not substantially complete before addition of the curing agent to the propellant mix then soft cures and non-reproducible mechanical properties will result. A long mix/purge cycle is currently required to accomplish substantially complete ammonia removal. A substantial savings would be realized in man hours and equipment turn-around time, and greater reproducibility of propellants properties from mix to mix should result, if this mix time could be reduced.
Therefore an object of this invention is to provide adducts of TEPAN which function as amine salt bonding agents with ammonium perchlorate (AP) while eliminating or minimizing generation of ammonia when incorporated into the mix during the propellant mixing cycle.
A further object of this invention is to provide amine salt bonding agents which reduce the mixing cycle time and which improve the mechanical properties of the finished propellant.
Still a further object of this invention is to provide amine salt bonding agents which are prepared by prereacting an amine bonding agent with an ammonium salt to yield amine salt bonding agents which minimize in situ ammonia generation during the mixing and cure cycles of propellant processing.